let _Vue = null;
class VueRouter {
  static install(Vue) {
    //1 判断当前插件是否被安装
    if (VueRouter.install.installed) {
      return;
    }
    VueRouter.install.installed = true;
    //2 把Vue的构造函数记录在全局
    _Vue = Vue;
    //3 把创建Vue的实例传入的router对象注入到Vue实例
    // _Vue.prototype.$router = this.$options.router
    _Vue.mixin({
      beforeCreate() {
        if (this.$options.router) {
          _Vue.prototype.$router = this.$options.router;
        }
      }
    });
  }
  constructor(options) {
    this.options = options;
    this.routeMap = {};
    let href = window.location.href;
    console.log(href);
    console.log(location);
    console.log(window.location.hash);
    //沒有hash，就加上
    if (!location.hash) {
      window.location.hash = "/";
    }
    // observable
    this.data = _Vue.observable({
      // current: "/"
      // current: window.location.pathname
      current: window.location.hash.slice(1) //去掉#
    });
    this.init();
  }
  init() {
    this.createRouteMap();
    this.initComponent(_Vue);
    this.initEvent();
    console.log(this.routeMap);
  }
  createRouteMap() {
    //遍历所有的路由规则 吧路由规则解析成键值对的形式存储到routeMap中
    this.options.routes.forEach(route => {
      console.log(route);
      this.routeMap[route.path] = route.component;
    });
  }
  initComponent(Vue) {
    Vue.component("router-link", {
      props: {
        to: String
      },
      render() {
        return (
          <a href={this.to} onClick={this.clickhander}>
            {this.$slots.default}
          </a>
        );
      },
      methods: {
        // clickhander(e) {
        //   history.pushState({}, "", this.to);
        //   this.$router.data.current = this.to;
        //   e.preventDefault();
        // }
        clickhander(e) {
          location.hash = this.to;
          this.$router.data.current = this.to;
          e.preventDefault();
        }
      }
    });
    const self = this;
    Vue.component("router-view", {
      render(h) {
        // self.data.current
        const cm = self.routeMap[self.data.current];
        return h(cm);
      }
    });
  }
  initEvent() {
    //监听手动触发location
    window.addEventListener("hashchange", () => {
      console.log(window.location.hash);
      this.data.current = window.location.hash.slice(1);
    });
  }
}

export default VueRouter;
